A balloon catheter is a medical device that includes an inflatable balloon carried by a elongated catheter shaft. The balloon catheter can be used to administer a variety of treatments. For example, in an angioplasty procedure, the balloon can be inflated to widen a constricted bodily vessel, such as a coronary artery. The balloon catheter can also be used to deliver a tubular member, such as an endoprosthesis (e.g., a stent), that is placed in the body to reinforce or to reopen a blocked vessel.
In angioplasty, the balloon can be used to treat a stenosis, or a narrowing of the bodily vessel, by collapsing the balloon and delivering it to a region of the vessel that has been narrowed to such a degree that blood flow is restricted. The balloon can be delivered to a target site by passing the catheter over an emplaced guidewire and advancing the catheter to the site. In some cases, the path to the site can be rather tortuous and/or narrow. Upon reaching the site, the balloon is then expanded, e.g., by injecting a fluid into the interior of the balloon. Expanding the balloon can expand the stenosis radially so that the vessel can permit an acceptable rate of blood flow. After use, the balloon is collapsed and withdrawn.
In stent delivery, the stent is compacted on the balloon and transported to a target site. The stent can include a metallic tubular member, and in some cases, the stent can include a polymeric graft material to form a covered stent or a stent-graft. Upon reaching the site, the balloon can be expanded to deform and to fix the stent at a predetermined position, e.g., in contact with the vessel wall. The balloon can then be collapsed and withdrawn.